Start consolidating cross-port file selection code into ui/base/dialogs.

ui/base/dialogs/base_shell_dialog.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef CHROME_BROWSER_UI_BASE_SHELL_DIALOG_H_
-#define CHROME_BROWSER_UI_BASE_SHELL_DIALOG_H_
+#ifndef UI_BASE_DIALOGS_BASE_SHELL_DIALOG_H_
+#define UI_BASE_DIALOGS_BASE_SHELL_DIALOG_H_
 #pragma once
 
 #include "ui/gfx/native_widget_types.h"
 
+namespace ui {
+
 // A base class for shell dialogs.
 class BaseShellDialog {
  public:
   // Returns true if a shell dialog box is currently being shown modally
   // to the specified owner.
   virtual bool IsRunning(gfx::NativeWindow owning_window) const = 0;
 
   // Notifies the dialog box that the listener has been destroyed and it should
   // no longer be sent notifications.
   virtual void ListenerDestroyed() = 0;
 
  protected:
   virtual ~BaseShellDialog() {}
 };
 
-#endif  // CHROME_BROWSER_UI_BASE_SHELL_DIALOG_H_
+}  // namespace
+
+#endif  // UI_BASE_DIALOGS_BASE_SHELL_DIALOG_H_